1. Field of the Invention
The invention concerns a calender assembly for treating a web of material, in particular a paper web, in a nip formed by a pair of press rolls, wherein at least one roll is heated.
2. Description of the Related Art
In order to allow rapid and unproblematic introduction of the paper web in calenders within a paper-making machine, the paper web runs essentially straight in the region of the calender, i.e. with a very low angle of wrap at the rolls.
To increase the smoothness of paper, often the use of heated rolls in the calender is required. The surface temperatures of over 200.degree. C. which are sometimes necessary in this case result in correspondingly high heat losses due to convection and radiation. For this reason, thermal protective hoods have been developed for the rolls, as known for example from DE-A-4 105 978. The relatively high expenditure is seen as a disadvantage here.